WVO on Diesel motorbike

Single Tank WVO systems and blending SVO WVO to thin it.

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WVO on Diesel motorbike

Postby alexanderfoti » Thu Jul 18, 2013 8:50 am

Hi all

I ride a home made diesel motorbike that uses a Direct injection 400 yanmar L100 engine.

It is well known in the diesel bike community, where this engine is popular, that it does not like veg oil. Mainly due to poor spray pattern and cokeing up of the injectors etc.

I have no idea where to start with converting this to run on WVO, straight, not interested in a 2 tank system as there is very limited space on a motorbike for such :)

So I know I need a modified injector tip, but what else?

Thanks in advance all!

Apologies for the double post!
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Re: WVO on Diesel motorbike

Postby David » Sun Jul 21, 2013 2:57 am

I spent an afternoon with Harry Lyon- Smith when he was in Sydney on his Veggie Bike around the world tour.

He was having trouble with his engine on WVO and subsequently,blends. He'd put in a few different engines after the first Yanmar which seemed to last quite well but had a premature failure from memory due to some problem not reliability related like a stone through the sump or whatever it was I now forget.

Talking to him and trying to figure out the problem I came to the conclusion that skimming the head on the engine to get the compression up and Trying to raise the injection pressure were probably good places to look at for adding longevity to these engines on WVO.
Knocking 1 MM or so off the head wouldn't be hard as that should be able to be accounted for by the adjustable rockers these engines have. Raising injection pressure could be done by playing with the springs in the Injection pump and injector which a good Diesel shop should be able to do easily.

As for the injector, I don't really know. I suspect the raising of the pressure should go a long way to getting the thicker oil to squirt finer. I wouldn't bother with heating the oil, if you look at the way the IP and injector work and are located, the oil will be heated by the engine well enough.

The other thing I think might help is a different exhaust. The originals tend to come out against an almost flat surface as they change direction. I think something that allows some what of a straight shot before a gentle curve may aid in removal of carbon bits and buildup in the engine.

Harrys problem seemed to stem around ring coking so I think the thing is to look at the causes of that and work from there. To this end I think getting the compress and injection pressures up would allow a lot cleaner burn on veg and that would be a help with the problem. I spoke to harry with a mind to blending but in the end I didn't think that was going to help a lot in his case from what he was describing.

Another thing is the fuel control on these engines is pretty poor and when they are at full throttle they over fuel greatly. That's always a bad thing with veg so if one could limit the amount of max fuel instead of the things smoking black, No doubt that would be a good step as well.
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Re: WVO on Diesel motorbike

Postby alexanderfoti » Sun Jul 21, 2013 3:34 am

Many thanks for the info.

I have read up about his experiences as well. I think the main reason he didnt want to blend with RUG is that he was travelling around the world on completely renewable sources? I am not so bothered, and would happily blend with 10% RUG if it reduces the viscocity enough.

1mm off the head sounds like an interesting idea. I was toying with the idea of boosting this little engine, which would invovled reducing the CR. Maybe a combination of boost and veg would be enough to keep the cr the same?

I have also read about increasing the pop pressure on the injectors to create a finer atomisation. I have heard that the injectors pumps are pretty finiky when it comes to back pressure, and I wonder if increasing the pop pressure too much on the injectors would prevent it injecting at all?

I have come to the same conclustion as well, most of the injector goes through the cylinder head and stays pretty heated throughout the time the engine is running, especially as mine has no cooling fins on the flywheel.
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Re: WVO on Diesel motorbike

Postby David » Sun Jul 21, 2013 8:40 am

alexanderfoti wrote:
I have read up about his experiences as well. I think the main reason he didnt want to blend with RUG is that he was travelling around the world on completely renewable sources? I am not so bothered, and would happily blend with 10% RUG if it reduces the viscocity enough.


It wasn't a matter of not wanting to use unleaded, it was a matter of me seeing no point in him doing it based on the problems he was having. I also though about water injection which has worked well for me but the problems he was experiencing with ring coking were so severe I couldn't see it being able to keep with the the removal of the deposits.

1mm off the head sounds like an interesting idea. I was toying with the idea of boosting this little engine, which would invovled reducing the CR. Maybe a combination of boost and veg would be enough to keep the cr the same?


Huh?
The fuel shouldn't have any effect on CR. That's a mathematical equation that fuel is not a part of.
I would suggest you need to build the engine to what you decide you are going to do before you do it. IF you are going to blow or turbo the engine, there are a lot of design things you need to consider and the fabrication of parts will be significant. If you have engineering skills and equipment I'd say go for it. IF not, then you ll want to have a friend with an engineering company or plenty of cash to throw at this idea.

My suggestion would be to get an engine running reliably on veg first then worry about forced aspiration.

I have also read about increasing the pop pressure on the injectors to create a finer atomisation. I have heard that the injectors pumps are pretty finiky when it comes to back pressure,


It's clear that you don't know anything about these or probably any engines from these statements.

The injectors on these pumps would be as near indestructible as could be built. There are simply a piston and a spring with a very elementary fuel metering system. They would have to be about as "UN-Finicky" as I could imagine. The piston runs direct off the cam so it's going to push anything that resembles liquid right through that pump. The rotating helical cam controls the amount of fuel by the effective piston travel but the pressure of the fuel I believe would remain the same.
I think the IP is pretty " Dumb" as it were and injection pressure would be controlled by the injector break pressure.


and I wonder if increasing the pop pressure too much on the injectors would prevent it injecting at all?
It would have to be a massive increase. From memory the fuel is compressed by the piston running off the cam in a hydrolocked fashion. You would have to nearly seal the fuel line to stop the fuel from the IP being emitted. I think the pressure the IP could deliver would be pretty much limited by what it took for something to break ad there isn't much that's going to break on one of those engines.
I can't see why you couldn't easily run 50% extra pop pressure on an injector as the volume would be the same, you'd just be effectively delaying the delivery to a higher buildup.

I have come to the same conclusion as well, most of the injector goes through the cylinder head and stays pretty heated throughout the time the engine is running, especially as mine has no cooling fins on the flywheel.


Why would there be cooling fins on the flywheel??
If you mean there are no fan blades, Then your engine must be water cooled.

You wuold learn a lot from pulling the IP n your engine and taking it apart to see how it ticks. There are easy to put together ( even I can do them!) and it would give you a few insights. Just make sure you line up the pin and ratchet on the fuel control when you put the pump back in or it will either not fire the injector or you'll have a wild run away engine when you go to start it back up again.
Last edited by David on Sun Jul 21, 2013 9:11 am, edited 1 time in total.
_____________________

I don't give a damn about what might or could happen until a significant group of people can tell me it HAS happened to them.
Until then, it's just more endless gloom and doom Veg folk law.
David
 
Posts: 333
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Location: Sydney Australia

Re: WVO on Diesel motorbike

Postby alexanderfoti » Sun Jul 21, 2013 9:05 am

David wrote:
It's clear that you don't know anything about these or probably any engines from these statements.



Thats hardly a fair assumption to make based on reading 2 or 3 paragraphs of text that I have written.

Agreed with running the engine correctly on veg, then boosting. That is not part of this discussion at the moment.

With regards to my comment on the fuel pump. It is a yanmar clone engine, and the quality of these fuel pumps are always questionable. My statement based on their unreliability is sourced from information from other users of this engine that have expreenced low injection pressure and 2-3 replacement pumps in 2000 miles. I fully understand how the fuel pump and engine operates.

It is an air cooled engine. The flywheels has fins that draw air through the middle of the flywheel ducting to force it around the cylinder and cylinder head. I have removed these and replaced them with an on demand electrical fan based cooling system to increase efficiency, especially as the engine was designed for stantionary use, and its now in a motorbike.

I would appreciate if you didnt make flash judgments on my knowledge of mechanical subjects please. All I am trying to do is gain more information and knowledge about runnign alrenative fuels, not trying to start an argument.
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Re: WVO on Diesel motorbike

Postby alexanderfoti » Sun Jul 21, 2013 9:19 am

David wrote:Another thing is the fuel control on these engines is pretty poor and when they are at full throttle they over fuel greatly. That's always a bad thing with veg so if one could limit the amount of max fuel instead of the things smoking black, No doubt that would be a good step as well.


I forgot to mention this, its setup correctly on mine, with only the movement required for acceleration, with the gov limit screw set correctly for smoke vs acceleration
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Re: WVO on Diesel motorbike

Postby coachgeo » Mon Jul 22, 2013 7:59 pm

These little engines used in diesel bikes are almost as much of a different breed as an automotive petrol engine is to an automotive diesel engine. For sure build quality is an issue. Rarely are they timed right from the factory..... especially the twins.

David what your saying about the IP and pistons within it...... sounds like their design is similar to the Bosch IP like was found on the old MB's like the 617. That sounds encouraging. Even those engines though folk did find ways to improve the injector to better atomize more viscus fuels. I know Elsbett is starting to sell Injectors modified for small industrial diesel engines. Plan to eventually put some in my Kubota that will be in a Triumph Tiger.

Interesting about IP heat soak you mention. Would be interesting to do an IR measure of the fuel coming out of the overflow (if their is one on these little ones.) Also a measure of the heat of the injector tubes to try to get an idea of how hot the fuel is in those lines.

My wonder with coking..... particularly this fellow's bike on the world tour.... any diesel... on constant load.... cokes more than with variable load. Now add to that an engine not finely tuned to the characteristics of the fuel in use; particularly WVO/SVO then like all the tractor and gen set studies that give WVO A bad name..... .... it is coke city. Your idea of water inject is spot on... plan that myself on my bike (though it will be a 3cyl diesel IDI )

wonder if cold starts and warm use at full load (but not full operating temp) on these little engines is the biggest of the coking culprits though. Would be interesting to experiment with long time of after glow for better combustion during cold start/warm use. That is if they have glow plugs. I've not spend tremendous amount of time looking over air cooled diesels. Hmmmm..... now that I think about it..... dont think they do. hmmmm.. might be something to consider adding if their is room.
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Re: WVO on Diesel motorbike

Postby David » Wed Jul 24, 2013 1:57 am

alexanderfoti wrote:

With regards to my comment on the fuel pump. It is a yanmar clone engine, and the quality of these fuel pumps are always questionable. My statement based on their unreliability is sourced from information from other users of this engine that have experienced low injection pressure and 2-3 replacement pumps in 2000 miles. I fully understand how the fuel pump and engine operates.


Sorry, but I have debunked far too many crap and idiotic theroys purported on the net to take much notice of them especialy when my own experiences and observations conflict.
Most people will parrot the same crap the person before said with no actual experience of the opinion they are putting across as hard fact.

Have you actually pulled one of these pumps apart and seen what is in them and how they work? I have done several and I can't see where there is any opportunity for them to be "Finicky". There is only about 6 components to the things and they are very straight forward in operation. I have had a few block up when I got the engine that had been standing of I have left standing but clean them out and they work fine n veg or anything else.

Perhaps you could link to some of the discussions where people say they have trouble so I could get a better idea of what " Finicky" actually means and where people are having trouble. It's always good to get the full picture because those that are having trouble could very well be using oil which is not properly processed or refined and if that is the case, you can't blame the equipment.

I have probably got a couple of hundred hours logged on a couple of Chinese Vertical engines on Straight veg and seen no problems what so ever.

Do you know of the specific reason the pumps these people are talking about have actually been replaced? what part of them failed or wore out?
As the things are bathed in engine oil one side and fuel on the other, it's hard to imagine them wearing or failing quickly.

That said I stand to be corrected and lean something new if there are common problems with these things.
_____________________

I don't give a damn about what might or could happen until a significant group of people can tell me it HAS happened to them.
Until then, it's just more endless gloom and doom Veg folk law.
David
 
Posts: 333
Joined: Thu Mar 06, 2008 4:12 am
Location: Sydney Australia


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